A sine function has an amplitude of 4/7, period of 2pi, horizontal shift of -3pi, and vertical shift of 1.

Question

What is the y-value of the positive function at x= pi/2? 

Answer 1

taking your data:

y = (4/7)sin (x + 3π) + 1

when x = π/2
y = (4/7)sin(π/2+3π) = 1
= (4/7)sin (7π/2) + 1
= (4/7)(-1) + 1
= 3/7